At the end of this week Germany’s top court will decide whether it is legal for pre-Euro 6 diesel vehicles to be banned by city councils. Both Stuttgart (Porsche’s home city) and Leipzig want to stop older diesel vehicles entering the city limits. If the court gives the policy the green light, the repercussions could be huge.

Last summer, Porsche bosses said that they would consider killing diesel altogether at the end of next year. Bringing the decision forward is not just because of the impact of the court case, it’s also likely to be a consequence of the new round of economy and pollution testing regimes (known as RDE and WLTP) which arrive this autumn.

Older-generation diesel engines could struggle to meet the new tests. Much better to shelve diesel until a new-generation of super-clean diesels arrive within the VW Group and Porsche can consider afresh re-launching diesel models.

But Porsche’s diesel decision might also have been influenced by the fact the Tesla Model S outsold the Mercedes S-Class in Western Europe last year. Certainly, that was helped by big Tesla sales in Norway, but it’s been some time since analysts declared that ‘premium’ values were now indivisible from ‘greenness’. In plain English, the sort of customers who buy the most expensive premium cars expect a vehicle to be genuinely environmentally friendly.

As Porsche has hinted, you can’t rule out a future diesel Porsche. After all, the next-gen big diesel engines could have mild-hybrid assistance to help further reduce pollution.

But engineering sources have also told Autocar, that future diesels are also likely to have their rampant performance reigned in because hard acceleration is a direct cause of high NOx emissions. And who could imagine a gently-accelerating diesel Porsche?

This makes no sense, porsche have said demand for diesels is dropping and xxxx has suggested a possible reason why, ie maybe people who can afford these high end cars are less worried about cost and economy, hence sales dropping off, if they did indeed prefer the diesel way and were mpg biased then surely sales wouldn't have dropped off? After all they are all big vehicles that traditionally do well with diesel engines.

Makes sense to pull them now and wait for better to come along, will we see other vag companies following or are their suv and large saloon diesel sales still high enough to remain justified?

Theres a simple, old and well proven solution to reducing NOx - water/meth injection - it lowers combustion temps and therefore NOx. Its also cheap, easy to fit and comes with the added benefit that as the injected water turns to steam and expands, it helps push the piston down giving a (free) slight increase in power.

on the 20th May a new diesel emissions test starts for the mot, the new limits will be that found on the manufacturers plate rather that the higher limits we have now. As a tester I have been checking the results we are getting now against the plate limits and about half the vans and cars we’re testing will fail the new test. The rectifying of this could lead to new injectors, DPF, egr valve and possibly removing the inlet manifold and cleaning out the carbon build up that will be restricting the air flow. It may even require the cylinder head to come off and be de-coked like in the old days. The bills for this work will be huge, injectors are at least £200 min each and can go as high as £1000 for some cars. I’m afraid that diesel is dead now and if you have one get rid quickly!

Just today the government has lost a third high Court case over it's air pollution strategy. Another example of the closing of ranks that is killing diesel. Yes you can add Urina or water/meth injection. But it is the increasing costs involved that are pushing diesel out of the market.

It'll be interesting to see if this is just a Porsche decision or whether some other marques within the VW Group will also abandon diesel, or even other manufacturers. I suspect, however, that other companies around the world will continue to stick with diesels for a few more years yet (while diesels still make sense with some type of cars and with some types of journeys) and that Porsche's decision rests solely with the fallout from dieselgate. I wouldn't be surprised to see some other VW Group marques reducing their diesel line-up over the next year or so. And I wouldn't be surprised to see Bentley dropping their diesel and replacing with a petrol hybrid.

I wonder how many people will continue to buy big heavy SUVs with a thirsty petrol engine? A conventional large car (e.g. BMW 5-series) with a petrol engine will be much cheaper to fuel (lighter, more aerodynamic) and as roomy inside. The end of the SUV dinosaurs? Here's hoping!